scholarly journals CD47: A Cell Surface Glycoprotein Which Regulates Multiple Functions of Hematopoietic Cells in Health and Disease

2013 ◽  
Vol 2013 ◽  
pp. 1-19 ◽  
Author(s):  
Per-Arne Oldenborg
Keyword(s):  
Cell Surface ◽  
Intracellular Signaling ◽  
Plasma Membranes ◽  
Cell Activation ◽  
Regulatory Protein ◽  
Hematopoietic Cells ◽  
Surface Glycoprotein ◽  
Proper Function ◽  
Cell Surface Glycoprotein ◽  
Extracellular Milieu

Interactions between cells and their surroundings are important for proper function and homeostasis in a multicellular organism. These interactions can either be established between the cells and molecules in their extracellular milieu, but also involve interactions between cells. In all these situations, proteins in the plasma membranes are critically involved to relay information obtained from the exterior of the cell. The cell surface glycoprotein CD47 (integrin-associated protein (IAP)) was first identified as an important regulator of integrin function, but later also was shown to function in ways that do not necessarily involve integrins. Ligation of CD47 can induce intracellular signaling resulting in cell activation or cell death depending on the exact context. By binding to another cell surface glycoprotein, signal regulatory protein alpha (SIRPα), CD47 can regulate the function of cells in the monocyte/macrophage lineage. In this spotlight paper, several functions of CD47 will be reviewed, although some functions may be more briefly mentioned. Focus will be on the ways CD47 regulates hematopoietic cells and functions such as CD47 signaling, induction of apoptosis, and regulation of phagocytosis or cell-cell fusion.

scholarly journals Rat Parotid Gland Acinar Cell Proliferation: Signal Transduction at the Plasma Membrane

1993 ◽  
Vol 4 (3) ◽  
pp. 537-543 ◽  
Author(s):  
K.R. Purushotham ◽  
Y. Nakagawa ◽  
M.G. Humphreys-Beher ◽  
N. Maeda ◽  
C.A. Schneyer
Keyword(s):  
Signal Transduction ◽  
Cell Proliferation ◽  
Cell Surface ◽  
Acinar Cell ◽  
Intracellular Signaling ◽  
Plasma Membranes ◽  
Surface Glycoprotein ◽  
Dependent Manner ◽  
Intact Cells ◽  
Cell Surface Glycoprotein

Galactosyltransferase (Gal Tase) is involved in a "receptor-ligand-type" interaction at the cell surface that mediates signal transduction following isoproterenol (ISO) treatment leading to acinar cell proliferation. Evidence is presented herein for the identification of the cell-surface glycoprotein signaling component. Using intact cells or isolated plasma membranes, the EGF-receptor (EGF-R) was specifically radiolabeled with [14C]-Galactose following ISO treatment. Injection of a polyclonal antibody monospecific for rat EGF-R also inhibited proliferation in a dose-dependent manner. The immunoaffinity purified receptor demonstrated altered lectin binding and increased in vitro Gal Tase substrate capacity following β-agonist treatment when compared with EGF-R isolated from control animals. When acinar cells were incubated in the presence of EGF, plasma membranes from control and ISO-treated animals showed autophosphorylation of EGF-R tyrosine moieties, transient increases in membrane associated phospholipase Cy, and increased cellular levels of cAMP. These properties of the tyrosine phosphate signaling pathway could be duplicated by the exogenous addition of bovine Gal Tase to ISO-treated cells but not control cells. The results suggest that cell surface Gal Tase interacts with a form of the EGF-R, having altered carbohydrate moieties to promote intracellular signaling for acinar cell proliferation.

scholarly journals Production of a monoclonal antibody against cell-surface glycoprotein of guinea pig adrenocortical cells.

1993 ◽  
Vol 41 (2) ◽  
pp. 235-243 ◽  
Author(s):  
Y Kameda ◽  
C Hirota
Keyword(s):  
Monoclonal Antibody ◽  
Sialic Acid ◽  
Cell Surface ◽  
Guinea Pig ◽  
Plasma Membranes ◽  
Surface Glycoprotein ◽  
Zona Fasciculata ◽  
Cell Surface Antigens ◽  
Adrenocortical Cells ◽  
Cell Surface Glycoprotein

A monoclonal antibody (MAb) that reacted with the cell-surface antigens of adrenocortical cells was generated against cell suspensions from guinea pig adrenal glands. Cell-surface membranes of the adrenocortical cells in all zones, i.e., zona glomerulosa, zona fasciculata, and zona reticularis, were labeled with the antibody. Adrenal medulla remained unlabeled. Immunoelectron microscopy showed that entire plasma membranes, i.e., plasma membranes between adjacent cells and free cell-surface membranes, including sinusoidal microvilli, were immunoreactive to the antibody. Immunoblot analysis demonstrated that the antibody bound to two prominent bands at molecular weights of approximately 62,000 and 110,000. Two bands were stained with lectin-digoxigenin conjugates. The 110 KD band reacted with Datura stramonium (DSA) and Maackia amurensis (MAA) agglutinins, indicating the presence of N-acetyl-glucosamine and sialic acid-linked alpha (2-3) to galactose; the 62 KD band reacted with SNA, indicating the presence of sialic acid-linked alpha (2-6) to galactose. In adrenocortical cells, the reaction pattern of Sambucus nigra (SNA) agglutinin was similar to that of the (MAb), whereas reaction patterns of DSA and MAA were different. Both neuraminidase digestion and prior absorption of the antibody with N-acetyl-neuraminic acid completely prevented the immunolabeling of adrenocortical cells. These results indicate that the MAb mainly recognizes the 2-6 sialylated cell-surface antigen of adrenocortical cells.

scholarly journals ERM family members as molecular linkers between the cell surface glycoprotein CD44 and actin-based cytoskeletons.

1994 ◽  
Vol 126 (2) ◽  
pp. 391-401 ◽  
Author(s):  
S Tsukita ◽  
K Oishi ◽  
N Sato ◽  
J Sagara ◽  
A Kawai ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Cell Surface ◽  
Plasma Membranes ◽  
Immunofluorescence Microscopy ◽  
Family Members ◽  
Integral Membrane Protein ◽  
Surface Glycoprotein ◽  
Cell Surface Glycoprotein ◽  
Bhk Cells ◽  
Triton X

The ERM family members, ezrin, radixin, and moesin, localizing just beneath the plasma membranes, are thought to be involved in the actin filament/plasma membrane association. To identify the integral membrane protein directly associated with ERM family members, we performed immunoprecipitation studies using antimoesin mAb and cultured baby hamster kidney (BHK) cells metabolically labeled with [35S]methionine or surface-labeled with biotin. The results indicated that moesin is directly associated with a 140-kD integral membrane protein. Using BHK cells as antigens, we obtained a mAb that recognized the 140-kD membrane protein. We next cloned a cDNA encoding the 140-kD membrane protein and identified it as CD44, a broadly distributed cell surface glycoprotein. Immunoprecipitation with various anti-CD44 mAbs showed that ezrin and radixin, as well as moesin, are associated with CD44, not only in BHK cells, but also in mouse L fibroblasts. Furthermore, immunofluorescence microscopy revealed that in both BHK and L cells, the Triton X-100-insoluble CD44 is precisely colocalized with ERM family members. We concluded that ERM family members work as molecular linkers between the cytoplasmic domain of CD44 and actin-based cytoskeletons.

scholarly journals Hyaluronate-CD44 Interactions Can Induce Murine B-Cell Activation

Blood ◽  
1997 ◽  
Vol 89 (8) ◽  
pp. 2901-2908 ◽  
Author(s):  
Asimah Rafi ◽  
Mitzi Nagarkatti ◽  
Prakash S. Nagarkatti
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Cell Activation ◽  
Critical Role ◽  
Surface Glycoprotein ◽  
B Cell Differentiation ◽  
B Cell Activation ◽  
Cell Surface Glycoprotein ◽  
Immunodeficient Mice

Abstract CD44 is a widely distributed cell surface glycoprotein whose principal ligand has been identified as hyaluronic acid (HA), a major component of the extracellular matrix (ECM). Recent studies have demonstrated that activation through CD44 leads to induction of effector function in T cells and macrophages. In the current study, we investigated whether HA or monoclonal antibodies (MoAbs) against CD44 would induce a proliferative response in mouse lymphocytes. Spleen cells from normal and nude, but not severe combined immunodeficient mice, exhibited strong proliferative responsiveness to stimulation with soluble HA or anti-CD44 MoAbs. Furthermore, purified B cells, but not T cells, were found to respond to HA. HA was unable to stimulate T cells even in the presence of antigen presenting cells (APC) and was unable to act as a costimulus in the presence of mitogenic or submitogenic concentrations of anti-CD3 MoAbs. In contrast, stimulation of B cells with HA in vitro, led to B-cell differentiation as measured by production of IgM antibodies in addition to increased expression of CD44 and decreased levels of CD45R. The fact that the B cells were responding directly to HA through its binding to CD44 and not to any contaminants or endotoxins was demonstrated by the fact that F(ab)2 fragments of anti-CD44 MoAbs or soluble CD44 fusion proteins could significantly inhibit the HA-induced proliferation of B cells. Also, HA-induced proliferation of B cells was not affected by the addition of polymixin B, and B cells from lipopolysaccharide (LPS)-unresponsive C3H/HeJ strain responded strongly to stimulation with HA. Furthermore, HA, but not chondroitin-sulfate, another major component of the ECM, induced B-cell activation. It was also noted that injection of HA intraperitoneally, triggered splenic B cell proliferation in vivo. Together, the current study demonstrates that interaction between HA and CD44 can regulate murine B-cell effector functions and that such interactions may play a critical role during normal or autoimmune responsiveness of B cells.

Cloning of the gene encoding TROP-2, a cell-surface glycoprotein expressed by human carcinomas

1995 ◽  
Vol 62 (5) ◽  
pp. 610-618 ◽  
Author(s):  
Mara Fornaro ◽  
Roberta Dell' Arciprete ◽  
Manuela Stella ◽  
Cecilia Bucci ◽  
Michele Nutini ◽  
...  
Keyword(s):  
Cell Surface ◽  
Surface Glycoprotein ◽  
Gene Encoding ◽  
Cell Surface Glycoprotein ◽  
Human Carcinomas ◽  
A Cell
Sign in / Sign up

Export Citation Format

Share Document